"For the most part, members of the Royal Family who are entitled to the style and dignity of HRH Prince or Princess do not need a surname, but if at any time any of them do need a surname (such as upon marriage), that surname is Mountbatten-Windsor," the Royal Family website explains.

William maintained this surname throughout his military career and was known as Lieutenant Wales, Hello! magazine reports. However, after marrying Kate Middleton in 2011, he became known as the Duke of Cambridge.

"The Duke and Duchess of Cambridge, accompanying Prince George, will be met on arrival at the school by the Head of Lower School, Helen Haslem, who will then escort Their Royal Highnesses to Prince George's reception classroom," Kensington Palace said in a statement, according to People magazine.

Anwar Hussein via Getty Images
Princess Diana with her sons Prince William and Prince Harry at Wetherby School on September 12, 1989 in London, England. It is Prince Harry's first day at school. (Photo by Anwar Hussein/WireImage)